we applied with a sponge at around a 3-1 ratio.. it was dirty lol ... left to dwell for around 15 to 20 mins then agitated with a bristle hand scrubber , then wet vac'd up to see result ... then applied another wetting of extreme to make sure we got deep into the pitting.. the second wetting worked a treat for the stubborn bits... wet vac'd up and then a wetting with clean water to neutralise..
pic 4 is a 50/50 clean and dirty shot from first wash ..
To be fair, it sounds like you put a lot more work into it hehe!